1. Field of the Invention
The present invention is directed to an air blanket warming system for incorporating a remote temperature sensor mounted adjacent the air blanket to provide a temperature signal representative of the heated air delivered to the air blanket and includes an improved conduit unit, remote temperature sensor unit, and improved air blanket.
2. Description of Related Art
It is well known to provide heated air to portions of the human body to maintain the human body temperature and/or to provide curative heat treatment to a patient. Air blankets are frequently used in operating rooms and critical care units and include a disposable air blanket that can be formed from a thin plastic or thin plastic paper configuration with appropriate apertures on one side of the blanket to bathe a patient with warm air. During the operation, the temperature of the patient can therefore be controlled. In a post-operative setting, it is possible to treat the patient for hypothennia. The concepts and use of the application of both heated and cold air is well known such as shown in U.S. Pat. No. 2,110,022 and U.S. Pat. No. 2,601,189.
Air blankets or thermal blankets generally use a heater unit that is portable and includes a cabinet having operator controls for setting temperatures with an internal heater unit and blower unit for delivering a controlled temperature of air to a flexible conduit. The flexible conduit extends from the cabinet to the thermal blanket. A temperature sensor is mounted at the egress of the cabinet housing to measure the heated air for purposes of controlling the heater unit within the housing. The flexible conduit is replaceable and connects to an appropriate coupler port on an inflatable thermal blanket. The blanket is disposable and is usually offset from the heater or source cabinet by a distance of approximately 24 to 36 inches of flexible hose length. The temperature sensor that is within the cabinet is physically and thermally isolated from the inflatable blanket by the hose and also frequently by interspaced components such as filters and connectors.
The flexible hose diameter is typically 21/2 inches and the air flow velocity is from a range of 1200 to 2000 feet a minute. The temperature of the warm air delivered to the flexible hose ranges from approximately ambient temperature to 48 degrees Centigrade. If the room temperature is about 20 degrees Centigrade, there is a drop of about 4 degrees Centigrade that can occur at the highest delivered air temperature as the air flows in the hose to the thermal blanket. This temperature drop, however, is highly dependent on not only the room temperature but also any turbulence generated in the hose air flow due to bends in the hose. Additional descriptions of thermal blankets can be found for example in U.S. Pat. Nos. 5,324,320, and 4,660,388.
The prior art is still seeking to improve the warming air apparatus for addressing the issue of hypotherapy in patients undergoing surgery and to further assist in the re-warming process after surgery or prolonged exposure to cold environment.